1. Field of the Invention
The present invention generally relates to camera apparatus such as a slit camera or the like and, more particularly, to a camera apparatus suitable for taking a picture of an object which is moving at high speed.
2. Description of the Prior Art
Slit cameras are widely used to decide the result of the race of objects which are moving at high speed. Because standard system television cameras cannot take a picture of an object which is moving at high speed, the slit camera is designed to capture an image of an object in a line fashion. FIG. 1A shows a simplified arrangement of the conventional slit camera.
Referring to FIG. IA, an object 1 is moving at high speed in the direction shown by an arrow D. An object image is picked up on a line sensor 3 through a relay lens 2 and a video signal V is generated from the line sensor 3 in response to a picked-up image 4 on the line sensor 3.
FIG. 1B shows another example of a conventional slit camera in which a slit image is focused on an area sensor 8.
As shown in FIG. 1B, a picked-up image of an object 1 which is moving at high speed in the direction shown by an arrow D becomes incident on each plane of a polygon mirror 7 through a relay lens 2 and a slit 6 formed on the slit plate 5. The polygon mirror 7 is rotated in the counter-clockwise direction shown by an arrow in FIG. 1B so that images reflected on the respective planes of the polygon mirror 7 from the slit 6 are sequentially projected onto the area sensor 8 as projected images 4, 4, 4 . . . Then, these projected images 4, 4, 4, . . . are output as the video signal V.
According to the prior-art slit camera shown in FIG. 1A, the camera apparatus must be formed by special sensors such as a line sensor or the like and the area sensor 8 such as a solid state image pickup device (hereinafter simply referred to as a CCD (charge-coupled device)) or the like utilized in ordinary cameras cannot be utilized as the image pickup means.
Even though the conventional slit camera using the polygon mirror as shown in FIG. IB can use the area sensor 8, such slit camera needs a mechanical rotating mechanism such as the slit plate 5 and the polygon mirror 7.
Further, the area sensor using only one CCD or the like cannot provide sufficient resolution.
Furthermore, if a color camera apparatus uses the slit plate 5 and the polygon mirror 7, then a mechanical rotating mechanism is needed, which causes deterioration in a color band characteristic as a result.